1. Field of the Invention
This invention generally relates to photographic apparatus and particularly to an adapter by which a self-contained camera can be coupled to an optical viewing device, such as an endoscope, so that an object image formed by an eyepiece of the viewing device can be photographed.
2. Description of the Prior Art
Endoscopes are optical viewing devices well-known for their ability to permit visualization of interior parts of the body which otherwise could not be observed because of their inaccessibility to the unaided eye. To accomplish this, endoscopes are generally provided with an objective lens, an optical relay system, and an eyepiece or occular. The objective lens operates to form a real image of an object under examination at some predetermined spatial location which is usually inside the body, and the relay system operates to transfer the real image along an elongated optical path to a convenient location outside of the body where it is then observed with the aid of the eyepiece.
The eyepiece is usually provided with an adjustment feature which permits people with different eye accommodation ability or vision to sharply focus on the real image. Observers with normal vision adjust the eyepiece so that image forming rays emerging from it are collimated, and observers with abnormal vision adjust the eyepiece so that image forming rays emerging from it converge or diverge slightly.
Photographing what the eye sees through such optical viewing devices is an established practice conducted with well-known photographic systems specially designed for endoscopic photography or with adapters by which existing self-contained cameras can be used with existing endoscopes. Examples of prior art systems and adapters for this purpose are shown and described in U.S. Pat. No. 3,638,643 issued to John E. Hotchkiss on Feb. 1, 1972 and entitled "Endoscope For Photographic Recording"; U.S. Pat. No. 3,918,072 issued to Toshihiro Imai et al. on Nov. 4, 1975 and entitled "Single-Lens Reflex Optical System For An Endoscope"; U.S. Pat. No. 3,995,287 issued to Karl Storz on Nov. 30, 1976 and entitled "Endoscopic Camera"; U.S. Pat. No. 3,900,021 issued to Anthony Peter Walter Makepeace et al. on Aug. 19, 1975 and entitled "Coupling For Endoscopes And Instruments Particularly Cameras"; U.S. Pat. No. 3,994,288 issued to Joseph G. Stumpf on Nov. 30, 1976 and entitled "Colposcope"; U.S. Pat. No. 3,490,347 issued to F. A. Seedhouse on Sept. 30, 1967 and entitled "Microscope Camera Adapter"; U.S. Pat. No. 4,157,216 issued to William T. Plummer on June 5, 1979 and entitled "Adapter For Optically Coupling A Photographic Camera With A Viewing Device"; and an article by Brian Stanford which appears in The Journal of Photographic Science, volume 3, 1955, and is entitled "Theoretical First Principles of Endoscopic Photography".
However, none of the foregoing publications deal directly with the specific problem with which the present invention is concerned. In particular, the primary object of the present invention is to provide an adapter by which a self-contained camera having an objective lens can be mechanically and optically coupled with an endoscope that is of the type especially adapted for photographic purposes to form an object image in a plane located a predetermined distance behind an eyepiece of the endoscope.
Other objects of the invention will in part be obvious and will in part appear hereinafter. The invention accordingly comprises the apparatus possessing the construction, combination of elements, and arrangement of parts which are exemplified in the following detailed disclosure.